In an injection-type freeze-drying apparatus, a raw material fluid is injected in a vacuum chamber, the raw material fluid being obtained by dissolving or dispersing a raw material for a medical product, a food product, a cosmetic product, or the like in a solvent or a disperse medium. In the above-mentioned injection process, the solvent takes heat from the raw material due to latent heat of vaporization thereof, and thus the raw material is frozen and dried. At this time, the raw material is formed into fine particles, and then is collected in a collector provided in a lower portion of the vacuum chamber. Further, in order to promote the above-mentioned drying action, the raw material is heated by a resistive-heating-type heater provided to the collector. It should be noted that in order to efficiently freeze the raw material within the vacuum chamber, the raw material is previously cooled before the raw material is injected in the vacuum chamber (for example, see Patent Document 1).
An apparatus (30) disclosed in Patent Document 2 transports frozen fine particles (F), which have been discharged from a vacuum freezing column (11), by use of a conveyor belt (22) provided in a drying chamber (21). It is proposed that in place of the conveyor belt (22), a vibrating conveyor may be used (for example, see Patent Document 2).
It should be noted that in the general freeze-drying method in the past, the raw material is frozen in advance before the raw material is received in the vacuum chamber, while in the injection-type freeze-drying method, the raw material is injected, formed into particles, and frozen by itself in the vacuum chamber. In view of the above-mentioned point, those methods are different from each other.